1. Field of the Invention
This invention relates to electric wave filters, to pi-section filters and, in particular, to a composite filter assembly integrally comprising a plurality of discrete pi-section LC filter units. The invention is also specifically directed to a method of manufacturing such a composite pi-section LC filter assembly. The filter assembly according to the invention finds use as a noise filter to suppress high frequency noise in a transmission path, among other applications.
2. Description of the Prior Art
The transmission of signals through the input-output device of a microcomputer, for example, necessitates the elimination of high frequency noise above two megahertz. This is possible by inserting pi-section LC filters in the transmission lines. By the pi-section LC filter is meant the filter comprising, in its simplest form, two capacitors and an inductance element connected to form a pi-network. It has been known to integrate these elements into a compact filter, as the combination of the individual elements would make the filter bulky and expensive.
Since the transmission path for a microcomputer comprises a plurality or multiplicity of lines, however, as many filters must be installed in juxtaposition. The use of individual pi-section LC filters in this and other comparable applications is therefore objectionable in view of their large space requirement and the trouble involved in connecting them to the respective lines. The total installation cost of the individual filters is also consideralby high.